Mitsubishi Colt Ralliart. Manual — part 77

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4A9>

13A-262

Inspection Procedure 12: Hesitation, sag, poor acceleration, stumble, surge

COMMENT ON TROUBLE SYMPTOM

• Failure is possibly caused by failed ignition sys-

tem, improper air-fuel ratio, improper compres-
sion pressure or other faults.

PROBABLE CAUSES

• Failed air-fuel ratio control system

• Failed ignition system

• Failed fuel system

• Failed intake and exhaust system

• Failed exhaust gas cleaning system

• Failed electronically controlled throttle valve sys-

tem

• Throttle valve fouled around

• Improper compression pressure

• Failed engine-ECU <M/T> or engine-CVT-ECU

<CVT>

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code

Q: Is the diagnosis code set?

YES :

Inspection chart for diagnosis code (Refer

to

P.13A-20

).

NO :

Go to Step 2 .

STEP 2. Check injector for operating sound.

• Check injector for operating sound (Refer to

P.13A-364

).

Q: Can operating sound be heard?

YES :

Go to Step 3 .

NO :

Check the injector system of the defective

cylinder.

(Refer to Code No. P0201: No. 1 Injector

System

P.13A-89

).

(Refer to Code No. P0202: No. 2 Injector

System

P.13A-94

).

(Refer to Code No. P0203: No. 3 Injector

System

P.13A-99

).

(Refer to Code No. P0204: No. 4 Injector

System

P.13A-104

).

STEP 3. M.U.T.-III data list

• Refer to Data List Reference Table

P.13A-331

.

a. Item 13: Intake air temperature sensor
b. Item 14: Throttle position sensor (sub)

c. Item 21: Engine coolant temperature sensor

d. Item 77: Accelerator pedal position sensor

(sub)

e. Item 78: Accelerator pedal position sensor

(main)

f. Item 79: Throttle position sensor (main)

Q: Are the check results normal?

YES :

Go to Step 4 .

NO :

Perform the diagnosis code classified check
Procedure for the sensor that has shown an
abnormal data value (Refer to Inspection
Chart for Diagnosis Code

P.13A-20

).

STEP 4. Check purge control solenoid valve
itself.

• Check purge control solenoid valve itself (Refer

to GROUP 17

− Emission Control System −

Evaporative Emission Control System

− Purge

Control Solenoid Valve Check

P.17-16

).

Q: Is the check result normal?

YES :

Go to Step 5 <CVT> , go to Step 6 <M/T> .

NO :

Replace purge control solenoid valve.

STEP 5. Check EGR valve (stepper motor) itself.

• Check EGR valve (stepper motor) itself [Refer to

GROUP 17

− Emission Control System −

Exhaust Gas Recirculation (EGR) System

− EGR

Valve (Stepper Motor) Check

P.17-20

].

Q: Is the check result normal?

YES :

Go to Step 6 .

NO :

Replace EGR valve (stepper motor).

STEP 6. M.U.T.-III data list

• Refer to Data List Reference Table

P.13A-331

.

a. Item 11: Oxygen sensor (front)
b. Item 59: Oxygen sensor (rear)

Q: Are the check results normal?

YES :

Go to Step 7 .

NO :

Perform the diagnosis code classified check
Procedure for the sensor that has shown an
abnormal data value (Refer to Inspection
Chart for Diagnosis Code

P.13A-20

).

Main

Index

Group

TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4A9>

13A-263

STEP 7. Visual check of ignition spark.

• Remove the spark plug and install it to the ignition

coil.

• Connect the ignition coil connector.

• Remove all injector connector.

• At the engine start, check each spark plug pro-

duces a spark.

Q: Is the check result normal?

YES :

Go to Step 9 .

NO :

Go to Step 8 .

STEP 8. Check spark plug.

• Check spark plug (Refer to GROUP 16 − Ignition

System

− On-vehicle Service − Spark Plug Check

and Cleaning

P.16-35

).

Q: Is the check result normal?

YES :

Check ignition circuit system (Refer to

Inspection Procedure 28

P.13A-320

).

NO :

Replace spark plug.

STEP 9. Check throttle body (throttle valve
portion) for contamination.

Q: Is the check result normal?

YES :

Go to Step 10 .

NO :

Clean throttle body (throttle valve portion)
(Refer to

P.13A-355

).

STEP 10. Check compression pressure.

• Check compression pressure (Refer to GROUP

11A

− On-vehicle Service − Compression Pres-

sure Check

P.11A-12

).

Q: Is the check result normal?

YES :

Go to Step 11 .

NO :

Repair.

STEP 11. Fuel pressure measurement.

• Fuel pressure measurement (Refer to Fuel Pres-

sure Test

P.13A-355

).

Q: Is the check result normal?

YES :

Replace engine-ECU <M/T> or

engine-CVT-ECU <CVT>.

NO :

Repair.

Main

Index

Group

TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4A9>

13A-264

Inspection Procedure 13: The feeling of impact or vibration when accelerating

COMMENT ON TROUBLE SYMPTOM

• Failure is possibly caused by failed ignition leak

with rise in spark plug-required voltage at accel-
eration, electronically controlled throttle valve
system soon.

PROBABLE CAUSES

• Failed ignition system

• Failed electronically controlled throttle valve sys-

tem

• Throttle valve fouled around

• Failed engine-ECU <M/T> or engine-CVT-ECU

<CVT>

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code

Q: Is the diagnosis code set?

YES :

Inspection chart for diagnosis code (Refer

to

P.13A-20

).

NO :

Go to Step 2 .

STEP 2. M.U.T.-III data list

• Refer to Data List Reference Table

P.13A-331

.

a. Item 14: Throttle position sensor (sub)
b. Item 77: Accelerator pedal position sensor

(sub)

c. Item 78: Accelerator pedal position sensor

(main)

d. Item 79: Throttle position sensor (main)

Q: Are the check results normal?

YES :

Go to Step 3 .

NO :

Perform the diagnosis code classified check
procedure for the sensor that has shown an
abnormal data value (Refer to Inspection
Chart for Diagnosis Code

P.13A-20

).

STEP 3. Check throttle body (throttle valve)
contamination.

Q: Is the check result normal?

YES :

Go to Step 4 .

NO :

Clean throttle body (throttle valve portion)
(Refer to

P.13A-355

).

STEP 4. Visual check of ignition spark.

• Remove the spark plug and install it to the ignition

coil.

• Connect the ignition coil connector.

• Remove all injector connector.

• At the engine start, check each spark plug pro-

duces a spark.

Q: Is the check result normal?

YES :

Replace engine-ECU <M/T> or

engine-CVT-ECU <CVT>.

NO :

Go to Step 5 .

STEP 5. Check spark plug.

• Check spark plug (Refer to GROUP 16 − Ignition

System

− On-vehicle Service − Spark Plug Check

and Cleaning

P.16-35

).

Q: Is the check result normal?

YES :

Check ignition circuit system (Refer to

Inspection Procedure 28

P.13A-320

).

NO :

Replace spark plug.

Main

Index

Group

TOC

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MPI) <4A9>

13A-265

Inspection Procedure 14: The feeling of impact or vibration when decelerating

COMMENT ON TROUBLE SYMPTOM

• Failure is possibly caused by insufficient air

intake due to failed electronically controlled sys-
tem.

PROBABLE CAUSES

• Failed electronically controlled system

• Throttle valve fouled around

• Failed engine-ECU <M/T> or engine-CVT-ECU

<CVT>

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code

Q: Is the diagnosis code set?

YES :

Inspection chart for diagnosis code (Refer

to

P.13A-20

).

NO :

Go to Step 2 .

STEP 2. M.U.T.-III data list

• Refer to Data List Reference Table

P.13A-331

.

a. Item 14: Throttle position sensor (sub)
b. Item 77: Accelerator pedal position sensor

(sub)

c. Item 78: Accelerator pedal position sensor

(main)

d. Item 79: Throttle position sensor (main)

Q: Are the check results normal?

YES :

Go to Step 3 .

NO :

Perform the diagnosis code classified check
Procedure for the sensor that has shown an
abnormal data value (Refer to Inspection
Chart for Diagnosis Code

P.13A-20

).

STEP 3. Check throttle body (throttle valve)
contamination.

Q: Is the check result normal?

YES :

Replace engine-ECU <M/T> or

engine-CVT-ECU <CVT>.

NO :

Clean throttle body (throttle valve portion)
(Refer to

P.13A-355

).

Main

Index

Group

TOC